A famine forced Britain's own prime minister to dismantle his party's tariffs

Britain's Corn Laws had taxed imported grain since 1815 to protect domestic landowners, keeping bread prices high. Conservative PM Robert Peel repealed them in 1846 as the Irish potato famine spread, splitting his own party but opening Britain to cheap foreign grain. The move is still cited as a landmark case of free trade winning out over protectionism.

— Wikipedia, Corn Laws — Historical overview, based on UK parliamentary history